Edmister

The acentric factor is calculated using Edmister s equation (1948) ... 

The accuracy depends on the fraction distilled it deviates particularly when determining the initial and final boiling points the average error can exceed 10°C. When calculating the ASTM D 86 curve for gasoline, it is better to use the Edmister (1948) relations. The Riazi and Edmister methods lead to very close results when they are applied to ASTM D 86 calculations for products such as gas oils and kerosene. 

Edmister, W.C. and K.K. Okamoto (1959), Applied hydrocarbon thermodynamics. Part 12 equilibrium flash vaporization correlations for petroleum fractions . Petroleum Refiner, Vol. 38, No. 8, p. 117. 

Feed analyses in terms of component concentrations are usually not available for complex hydrocarbon mixtures with a final normal boihng point above about 38°C (100°F) (/i-pentane). One method of haudhug such a feed is to break it down into pseudo components (narrow-boihng fractions) and then estimate the mole fraction and value for each such component. Edmister [2nd. Eng. Chem., 47,1685 (1955)] and Maxwell (Data Book on Hydrocarbons, Van Nostrand, Princeton, N.J., 1958) give charts that are useful for this estimation. Once values are available, the calculation proceeds as described above for multicomponent mixtures. Another approach to complex mixtures is to obtain an American Society for Testing and Materials (ASTM) or true-boihng point (TBP) cui ve for the mixture and then use empirical correlations to con-strucl the atmospheric-pressure eqiiihbrium-flash cui ve (EF 0, which can then be corrected to the desired operating pressure. A discussion of this method and the necessary charts are presented in a later subsection entitled Tetroleum and Complex-Mixture Distillation. ... 

Because of the time and expense involved in conducting laboratoiy distillation tests of all three basic types, it has become increasingly common to use empirical correlations to estimate the other two distillation curves when either the ASTM, TBP, or EFN- curve is available. Preferred correlations given in the API Technical Data Book—Petroleum Refining (op. dt.) are based on the work of Edmister and Pollock [Chem. Eng. Prog., 44, 905 (1948)], Edmister and Okamoto [Pet. Refiner, 38(8), 117 (1959) 38(9), 271 (1959)], Maxwell Data Book on... 

FIG. 13-85 Average tnie-boiling-point distillation curves of crude oils. (Prom VP E. Edmister, Applied Hydrocarbon Thermodynamics, vol. I, 1st ed, 1961 Gulf Publishing Companif, Houston, Texas, Used with peirrussion All nghts leseived.)... 

For systems in which the concentrations are large and the stripping factor S may vary along the tower, the following Edmister eqnadons... 

For systems in which the absorption factor A for each component is not constant throughout the tower, an effective absorption factor for use in the equations just presented can be estimated by the Edmister formula... 

Edmister, W.C., Applied Hydrocarbon Dynamics, Vol. 1, Gulf Publishing Co., Houston, Texas, pp. 1-3, 1961. 

Edmister Method (1947). Briefly, the Edmister absorption method (1947) with a known rich gas going to a fixed tower is as follows ... 

Figure 1. This graph shows the abosrption and stripping factors, Eg and E, versus effective values, Ae and Se (efficiency functions). (By permission, W. C. Edmister, Petroleum Engineer, September, 1947 Series to January, 1948.)...

Edmister Method (1957). Edmister has developed an improved procedure that features equations combining absorption and stripping functions as follows ... 

Edmister, W. C., Petroleum Engineer, September, 1947 Series to January, 1948. 

Edmister, W. C., and Lee., B. I., Applied Hydrocarbon Thermodynamics, Volume 1, second edition. Houston, Texas Gulf Publishing Co.,... 

The Edmister method for absorption use factors for overall stripping and absorption built up by combining column top and bottom factors. 

Edmister, Wayne C. and Lee, Eying Ik, Applied Hydrocarbon Thermndv mimics, Vol. 1, Second Edition, Hou,ston, TX Gulf Publishing Company, 1984. 

Figure B-5. Carboii uiuaiuc pressui iithalpy diagram. (From Edmister and Le i, Second Edition, Gulf Publishing c ompany, Houston, TX, 1984.)...

Thermodynamic data on fluids can be found in Perry and Green (1984) or Edmister and Lee (1984), among others. The method or determining the thermodynamic data will be explained in detail in Step 3. 

Several methods [17, 18, 29, 40, 62, 67, 223] for handling this design have been offered and each has introduced a concept to improve some feature. An approximation method combination of Kremser-Brown [40, 67] and a more complete method of Edmister [18] will be summarized. Figure 8-57 summarizes the system and terminology. The accepted nomenclature for absorption and stripping is located on page 121. 

Figure 8-57. Flow diagram of absorption-stripping for hydrocarbon recovery from gaseous mixture. Used by permission, Edmister, W. C., Petroleum Erjgr., Sept. (1947) to January (1948).

A graphical solution is presented by Edmister [18] and handled like step-wise distillation. 

This method [18] is well suited to handling the details of a complicated problem, yet utilizing the concept of average absorption and stripping factors. It also allows for the presence of solute components in the solvent and the loss of lean oil into the off gas. Reference 18 presents more details than are included here. Reference 18 is Edmister s original publication of the basic method for absorbers and strippers. Reference 18 also generates the... 

Edmister s effective absorption factor Outside surface area of absorber, ft ... 

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